Centriolar satellites are required for efficient ciliogenesis and ciliary content regulation.

Centrosome is the main microtubule organizing center of the cell. It has the role in cell division, cell shape and migration. Other than these roles, centrosome has an important function which is forming primary cilium. Primary cilium is a microtubule-based organelle serving as signaling hub for the cell. Structural or functional defects associated with centrosome/cilium complex lead to genetic diseases called ciliopathies. In order to understand molecular mechanism under ciliopathies, it is important to understand how centrosome/cilium complex is regulated in time and space. Centriolar satellites are the third component of the centrosome/cilium complex In the second chapter of my thesis, I characterized the cells without centriolar satellites in terms of ciliogenesis and ciliary function. I established the satellite-less cells by knocking-out PCM1 gene in inner medullary collecting duct (IMCD3) cells. PCM1 is the scaffolding protein of the centriolar satellites. Satellite-less IMCD3 cells do not ciliate efficiently as much as control cells. Content and function of cilia formed by satellite-less cells are also different. To understand how cellular process are affected in PCM1 knock-out cells, I applied tandem mass tag (TMT) labeling‐based quantitative analysis to compare the global proteome control and satellite-less cells. This analysis revealed that many processes such as actin cytoskeleton, cell migration and adhesion, endocytosis, neuronal processes are affected in the absence of PCM1 protein. With these observations, I showed that centriolar satellites are important to regulate ciliogenesis, ciliary content and function. However, the mechanism behind this regulation is poorly understood. In the third chapter of my thesis, I applied the miniTurbo labeling method to compare interaction partners of PCM1 in asynchronous and ciliated cells. The aim of this chapter to find interaction partners of PCM1 specific to ciliated cells to explain mechanism of regulation by centriolar satellites during ciliogenesis. After miniTurbo experiments and mass spectrometry analysis, we determined a set of protein which interact with PCM1 in ciliated cells. Among these proteins, we checked the localization and function of the TBC1D31 protein by loss of function experiments. In this chapter, we determined the set of protein might have a role in regulation of ciliogenesis with centriolar satellites. The interactions between these proteins with PCM1 and their relationship in the regulation of ciliogenesis are going to be explored in our future studies.